CN110940843A - High-frequency current demodulation device for fiber grating current sensor - Google Patents
High-frequency current demodulation device for fiber grating current sensor Download PDFInfo
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- CN110940843A CN110940843A CN201911120632.0A CN201911120632A CN110940843A CN 110940843 A CN110940843 A CN 110940843A CN 201911120632 A CN201911120632 A CN 201911120632A CN 110940843 A CN110940843 A CN 110940843A
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- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/24—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using light-modulating devices
- G01R15/245—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using light-modulating devices using magneto-optical modulators, e.g. based on the Faraday or Cotton-Mouton effect
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Abstract
The application discloses a high frequency current demodulating equipment for fiber grating current sensor includes: the tunable filter is used for receiving the reflected light of the fiber bragg grating and outputting filtering laser with different light intensities; the data processing module is used for performing photoelectric conversion and generating a voltage control signal; the wavelength tuning module is provided with a differential amplifying module and a bridge circuit, wherein the signal input end of the differential amplifying module is connected to the connecting end of the bridge circuit, the power supply input end of the differential amplifying module is connected to the output end of the data processing module and used for receiving a voltage control signal, the amplifying output end of the differential amplifying module is connected to the tuning end of the tunable laser, the differential amplifying module is used for applying laser tuning voltage to the tunable laser, and the connecting end of the bridge circuit is connected to the low voltage end of the wavelength tuning module through a capacitor. Through the technical scheme in the application, the problem that the working point is deviated due to the ambient temperature and the circuit noise is solved, and meanwhile, the high-frequency current is demodulated.
Description
Technical Field
The application relates to the technical field of current detection devices, in particular to a high-frequency current demodulation device for a fiber grating current sensor.
Background
The detection of high-frequency current and harmonic wave is carried out by utilizing the fiber bragg grating, one method is to adopt an intensity demodulation method, although the method can solve the measurement of signals with dozens of kHz and even higher frequency, the intensity demodulation method has very high requirements on the working conditions of a working point, and the ambient temperature and circuit noise can cause the deviation of the working point, thereby further influencing the demodulation precision and the measurement accuracy of the sensor. Especially for sudden interfering signal occurrences, this can result in a loss of the static operating point of the sensor.
The other is to adopt a wavelength demodulation method, which is to change and analyze the amplitude and frequency of a measured signal by measuring the wavelength value of the fiber grating, although the problems in the intensity demodulation method can be overcome, the current wavelength demodulation method is mostly about 1kHz sampling frequency and cannot meet the measurement of high-frequency current.
Disclosure of Invention
The purpose of this application lies in: the high-frequency current demodulation device for the fiber bragg grating current sensor is used for demodulating the high-frequency current while solving the problem that the working point is deviated by the ambient temperature and circuit noise.
The technical scheme of the application is as follows: the utility model provides a high frequency current demodulating equipment for fiber grating current sensor, current demodulating equipment is including the drive module, tunable laser, light path coupler and the fiber grating current transformer that connect gradually, and drive module drive tunable laser produces single mode laser, and the fiber grating of fiber grating current transformer is gone into to single mode laser behind the light path coupler, and current demodulating equipment still includes: the tunable filter, the data processing module and the wavelength tuning module; the tunable filter is used for receiving the reflected light of the fiber bragg grating and outputting filtering laser with different light intensities; the data processing module is used for performing photoelectric conversion on the filtered laser to generate a voltage control signal and sending the voltage control signal to the wavelength tuning module; the wavelength tuning module is provided with a differential amplifying module and a bridge circuit, wherein the signal input end of the differential amplifying module is connected to the connecting end of the bridge circuit, the power supply input end of the differential amplifying module is connected to the output end of the data processing module and used for receiving a voltage control signal, the amplifying output end of the differential amplifying module is connected to the tuning end of the tunable laser, the differential amplifying module is used for applying laser tuning voltage to the tuning end of the tunable laser according to the voltage control signal, and the connecting end of the bridge circuit is connected to the low voltage end of the wavelength tuning module through a capacitor.
In any of the above technical solutions, further, two first voltage dividing resistors R1 and R2 with equal resistance values are connected in series to a first bridge arm of the bridge circuit, and a connection end of the first bridge arm is connected to a first signal input end of the differential amplification module
The connecting end of the first bridge arm is also connected to a low-voltage end through a first capacitor C1; a thermistor R4 and a second divider resistor R3 are connected in series on a second bridge arm of the bridge circuit, and the connecting end of the second bridge arm is connected with a second signal input end of the differential amplifying module
The connection end of the second bridge arm is also connected to the low voltage end through a second capacitor C2, wherein the thermistor R4 is located at the tuning end of the tunable laser.
In any of the above technical solutions, further, a resistor R5 is connected in series between two impedance matching ends of the differential amplification module.
In any one of the above technical solutions, further, the data processing module specifically includes: the device comprises a photoelectric conversion unit, an analog-to-digital conversion unit and a signal processing unit; the photoelectric conversion unit is used for performing photoelectric conversion on the filtered laser output by the tunable filter to generate a photoelectric signal and sending the converted electric signal to the analog-to-digital conversion unit; the analog-to-digital conversion unit is used for performing digital-to-analog conversion on the received electric signal to generate a digital signal and sending the converted digital signal to the signal processing unit; the signal processing unit is used for generating a voltage control signal according to the wavelength adjusting algorithm and the received digital signal.
The beneficial effect of this application is:
the problem that the working point of the tunable laser is deviated due to the ambient temperature and circuit noise is solved, and meanwhile, the demodulation of high-frequency current in the tunable laser is realized. The following technical effects are realized:
(1) the output voltage of the wavelength tuning module and the operation temperature of the tunable laser present a very high linear change relationship, and then the tuning of the emitted laser is carried out;
(2) the output voltage of the wavelength tuning module and the center wavelength of the tuned laser are continuously changed within a specified range;
(3) the scanning frequency was increased so that the fastest scanning time of one cycle was 0.4 ms.
Drawings
The advantages of the above and/or additional aspects of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic diagram of a high frequency current demodulation arrangement for a fiber grating current sensor according to one embodiment of the present application;
FIG. 2 is a schematic flow diagram of a high frequency current demodulation method for a fiber grating current sensor according to one embodiment of the present application;
FIG. 3 is a schematic diagram of a wavelength sweep control module according to one embodiment of the present application;
FIG. 4 is a wavelength sweep control module temperature versus control voltage relationship according to one embodiment of the present application;
FIG. 5 is a diagram illustrating a relationship between a voltage and a center wavelength according to an embodiment of the present application;
FIG. 6 is a schematic illustration of a wavelength scan according to an embodiment of the present application.
Detailed Description
In order that the above objects, features and advantages of the present application can be more clearly understood, the present application will be described in further detail with reference to the accompanying drawings and detailed description. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, however, the present application may be practiced in other ways than those described herein, and therefore the scope of the present application is not limited by the specific embodiments disclosed below.
As shown in fig. 1 and fig. 2, this embodiment provides a high-frequency current demodulating apparatus for a fiber grating current sensor, where the current demodulating apparatus includes a driving module, a tunable laser, an optical path coupler, and a fiber grating current transformer, which are connected in sequence, the driving module drives the tunable laser to generate a single-mode laser, the single-mode laser passes through the optical path coupler and then is pumped into a fiber grating of the fiber grating current transformer, and the current demodulating apparatus further includes: the tunable filter, the data processing module and the wavelength tuning module; the tunable filter is used for receiving the reflected light of the fiber bragg grating and outputting filtering laser with different light intensities;
specifically, the fiber grating current transformer in this embodiment mainly includes a magnetic conductive coil (magnetic flux collecting ring), a magnetic strain material, and a fiber grating attached to the surface of the magnetic strain material, where the detected electrified cable passes through the magnetic conductive coil, and when a current in the cable flows through the magnetic conductive coil, a circumferential magnetic field of the cable is coupled into the magnetic conductive coil to drive the magnetic strain material to deform, so as to pull the fiber grating, and a gap of the fiber grating generates a change having the same period as the current.
Under the drive of the drive module, the tunable laser pumps a single-mode laser into the optical path coupler, the single-mode laser enters the fiber grating with the periodically changed gap after passing through the optical path coupler, so that the wavelength of reflected light in the fiber grating is periodically changed, the reflected light with the periodically changed wavelength enters the tunable filter through the optical path coupler again, and the tunable filter in the embodiment is a tunable F-P filter.
Because the light intensities of the reflected lights with different wavelengths are different, the tunable F-P filter outputs the filtered laser with different light intensities to the photoelectric conversion unit of the data processing module.
In this embodiment, the data processing module specifically includes: photoelectric conversion unit, analog-to-digital conversion unit, signal processing unit. The tunable laser tuning device comprises a tunable filter, a photoelectric conversion unit, an analog-to-digital conversion unit, a signal processing unit and a signal processing unit, wherein the tunable filter is used for filtering laser output by the tunable filter, converting the filtered laser output by the tunable filter into a photoelectric signal, sending the converted electric signal to the analog-to-digital conversion unit, converting the received electric signal into a digital signal by the analog-to-digital conversion unit, sending the converted digital signal to the signal processing unit, and finally generating a voltage control signal by the signal processing unit according to a wavelength adjusting algorithm and the received digital signal so as to facilitate a wavelength tuning module to complete tuning of a tunable laser.
Specifically, the signal processing unit may be a CPU unit, or may be formed by an FPGA unit and an ARM unit, where the FPGA unit implements high-speed signal processing on the analog-to-digital conversion module, and the ARM unit mainly implements digital signal processing and a wavelength tuning algorithm. Preferably, the signal processing unit can be further provided with an RJ45 interface to realize TCP/IP data transmission with a remote data server.
The specific process of the ARM unit performing digital signal processing and wavelength tuning algorithm is shown in fig. 2. In this embodiment, the voltage V of the tunable laser is used as a control variable, first, all control variables are initialized through initialization, then the control voltage V starts from 0, and performs cyclic increment, and when the voltage V reaches the maximum value 40, the voltage V is calculated from 0 again, wherein the increment step of the voltage V is determined according to the laser wavelength scanning precision, and the increment step is set to 1 in this embodiment.
The wavelength tuning module is provided with a differential amplifying module and a bridge circuit, wherein the signal input end of the differential amplifying module is connected to the connecting end of the bridge circuit, the power supply input end of the differential amplifying module is connected to the output end of the data processing module and used for receiving a voltage control signal, the amplifying output end of the differential amplifying module is connected to the tuning end of the tunable laser, the differential amplifying module is used for applying laser tuning voltage to the tuning end of the tunable laser according to the received voltage control signal, and the connecting end of the bridge circuit is connected to the low voltage end of the wavelength tuning module through a capacitor.
Specifically, as shown in fig. 3, the wavelength tuning module in this embodiment is a laser temperature control circuit, wherein the differential amplification module is formed by an INA122P chip, and the differential amplification module receives a voltage control signal (voltage V) from a signal processing unit in the data processing module, and realizes current direction control of the laser peltier by using the differential amplification module and the bridge circuit, thereby realizing temperature increase and decrease control.
Furthermore, two first divider resistors R1 and R2 with equal resistance values are connected in series to a first bridge arm of the bridge circuit, and a connection end of the first bridge arm is connected to a first signal input end of the differential amplification module
The connecting end of the first bridge arm is also connected to a low-voltage end through a first capacitor C1;
a thermistor R4 and a second divider resistor R3 are connected in series on a second bridge arm of the bridge circuit, and the connecting end of the second bridge arm is connected with a second signal input end of the differential amplifying module
The connection end of the second bridge arm is also connected to the low-voltage end through a second capacitor C2, wherein the thermistor R4 is located at the tuning end of the tunable laser, that is, the tuning of the current in the thermistor R4 is realized by tuning the voltage at the two ends of the thermistor R4, and further the tuning of the tunable laser is realized.
Further, a resistor R5 is connected in series between the two impedance matching terminals (pin 1 and pin 5) of the differential amplification module.
Two bridge arms of the bridge circuit are respectively connected with a first voltage-dividing resistor R1 and a second voltage-dividing resistor R2, a second voltage-dividing resistor R3 and a thermistor R4, the thermistor R4 is positioned at a tuning end of the tunable laser, and the current of the thermistor R4 is regulated and controlled by adjusting the voltage applied to two ends of the thermistor R4, so that the tuning of the laser emitted by the tunable laser can be realized.
In order to avoid the influence of alternating current noise on the input signal of the differential amplifying module, capacitors C1 and C2 are connected in series between the two connecting ends of the bridge circuit and the low voltage end of the circuit. Similarly, to filter and noise-proof the output signal of the differential amplification module, a filter noise-proof capacitor C3 is connected in series with the low voltage terminal at its amplification output terminal V +.
Signal input end of differential amplification module
And
the (pins 2 and 3) are connected to the two terminals of the bridge circuit, respectively, and the power supply input Vo (pin 7) of the differential amplifying module is connected to the output ADCINAO of the signal processing unit, so as to receive the control signal voltage V. The other supply input terminal V- (pin 4) is connected to the low voltage terminal in the circuit.
The tuning process of the wavelength tuning module comprises the following steps: the voltage at two ends of the thermistor R4 is acquired through a bridge circuit and input into differential input ends (pins 2 and 3) of an INA122P (differential amplification module), voltage signals are compared in the INA122P according to the input value of ADCINA0V0, the comparison difference is output and fed back to two ends of the thermistor R4 through an amplification output end V + (pin 6), and the current of the thermistor R4 is regulated.
In order to verify the current adjusting apparatus in this embodiment, the resistances of the first voltage-dividing resistors R1, R2 and the second voltage-dividing resistor R3 are set to 8.2k Ω, the values of the first capacitor C1, the second capacitor C2 and the capacitor C3 are set to 0.1 μ F, the value of the resistor R5 is set to 2.2k Ω, and the supply voltage of the bridge circuit is set to 3.3V. The simulation curves obtained by the experiment are shown in fig. 4 to 6, and the data in the graphs can prove that:
(1) the temperature of the laser and the control voltage of the differential amplification module INA122P show a very high linear variation relationship;
(2) by the current adjusting device in the embodiment, the central wavelength of the tunable laser can be linearly controlled to continuously change within the range of 1520 and 1560 nm;
(3) in the test process, the CPU unit is used as the signal processing unit to send out the PWM control voltage signal, so that the fastest scanning period of the current demodulation apparatus in this embodiment is 0.4 ms.
The technical scheme of the present application is described in detail above with reference to the accompanying drawings, and the present application provides a high-frequency current demodulation device for a fiber grating current sensor, wherein a tunable filter is used for receiving reflected light of a fiber grating and outputting filtered laser light with different light intensities; the data processing module is used for performing photoelectric conversion and generating a voltage control signal; the wavelength tuning module is provided with a differential amplifying module and a bridge circuit, wherein the signal input end of the differential amplifying module is connected to the connecting end of the bridge circuit, the power supply input end of the differential amplifying module is connected to the output end of the data processing module and used for receiving a voltage control signal, the amplifying output end of the differential amplifying module is connected to the tuning end of the tunable laser, the differential amplifying module is used for applying laser tuning voltage to the tunable laser, and the connecting end of the bridge circuit is connected to the low voltage end of the wavelength tuning module through a capacitor. Through the technical scheme in the application, the problem that the working point is deviated due to the ambient temperature and the circuit noise is solved, and meanwhile, the high-frequency current is demodulated.
The steps in the present application may be sequentially adjusted, combined, and subtracted according to actual requirements.
The units in the device can be merged, divided and deleted according to actual requirements.
Although the present application has been disclosed in detail with reference to the accompanying drawings, it is to be understood that such description is merely illustrative and not restrictive of the application of the present application. The scope of the present application is defined by the appended claims and may include various modifications, adaptations, and equivalents of the invention without departing from the scope and spirit of the application.
Claims (4)
1. The utility model provides a high frequency current demodulating equipment for fiber grating current sensor, a serial communication port, current demodulating equipment is including the drive module, tunable laser, light path coupler and the fiber grating current transformer that connect gradually, the drive module drive tunable laser produces single mode laser, single mode laser passes through pump in behind the light path coupler fiber grating current transformer's fiber grating, current demodulating equipment still includes: the tunable filter, the data processing module and the wavelength tuning module;
the tunable filter is used for receiving the reflected light of the fiber bragg grating and outputting filtering laser with different light intensities;
the data processing module is used for performing photoelectric conversion on the filtered laser to generate a voltage control signal and sending the voltage control signal to the wavelength tuning module;
the wavelength tuning module is provided with a differential amplification module and a bridge circuit, a signal input end of the differential amplification module is connected to a connecting end of the bridge circuit, a power supply input end of the differential amplification module is connected to an output end of the data processing module and used for receiving the voltage control signal, an amplification output end of the differential amplification module is connected to a tuning end of the tunable laser, the differential amplification module is used for applying laser tuning voltage to the tuning end of the tunable laser according to the voltage control signal, and the connecting end of the bridge circuit is connected to a low voltage end of the wavelength tuning module through a capacitor.
2. The high-frequency current demodulating apparatus for a fiber grating current sensor according to claim 1,
two first divider resistors R1 and R2 with equal resistance values are connected in series on a first bridge arm of the bridge circuit, and a connecting end of the first bridge arm is connected to a first signal input end of the differential amplification module
The connecting end of the first bridge arm is also connected to the low-voltage end through a first capacitor C1;
a thermistor R4 and a second divider resistor R3 are connected in series on a second bridge arm of the bridge circuit, and a connecting end of the second bridge arm is connected to a second signal input end of the differential amplification module
The connection end of the second bridge arm is further connected to the low voltage end through a second capacitor C2, wherein the thermistor R4 is located at the tuning end of the tunable laser.
3. The high-frequency current demodulating apparatus for a fiber grating current sensor according to claim 2, wherein a resistor R5 is connected in series between the two impedance matching terminals of the differential amplification module.
4. The high-frequency current demodulation device for the fiber grating current sensor according to claim 1, wherein the data processing module specifically comprises: the device comprises a photoelectric conversion unit, an analog-to-digital conversion unit and a signal processing unit;
the photoelectric conversion unit is used for performing photoelectric conversion on the filtered laser output by the tunable filter to generate a photoelectric signal and sending the converted electric signal to the analog-to-digital conversion unit;
the analog-to-digital conversion unit is used for performing digital-to-analog conversion on the received electric signal to generate a digital signal and sending the converted digital signal to the signal processing unit;
the signal processing unit is used for generating the voltage control signal according to a wavelength adjusting algorithm and the received digital signal.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111551870A (en) * | 2020-05-18 | 2020-08-18 | 国网江苏省电力有限公司无锡供电分公司 | Insulator leakage current monitoring device and method based on fiber bragg grating |
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Application publication date: 20200331 |